College of Agriculture & Natural Resources

Permanent URI for this collection

https://ir.knust.edu.gh/handle/123456789/13

Browse

Recent Submissions

Now showing 1 - 5 of 577
  • No Thumbnail Available
    Item
    Development of a model framework for simultaneous synthesis and selection of Anaerobic Digester Structures
    (November, 2019) Rejoice Ntiriwaa Ossei-Bremang;
    The anaerobic treatment process has increasingly been recognized as an efficient technology for sustainable nutrient recovery, renewable energy generation, and environmental sanitation due to its strong potential to mitigate current energy resource and climate change challenges. However, the success of industrial-scale anaerobic digestion is only possible if the following two prerequisite factors are met: availability of a sustainable supply of organic feedstock and design of optimal process configurations containing appropriate digester subunits that are well adapted to the characteristics of the feedstock of interest. A lot of combinations of the fundamental anaerobic digester types exist, which becomes impossible to test all the possibilities in order to determine the one with the absolute best performance. This study did not focus attention on devising new digesters with the aim of improving the performance of the system, but rather optimally arranged some combinations of plug flow reactors (PFRs) and continuous stirring tank reactor (CSTR) systems. The objective of study was to establish a framework based on multi-criteria decision analysis, for optimal selection of anaerobic digesters and practical implementation of digester networks, which is amendable to any substrate and digester configuration. Anaerobic treatability study was performed using pineapple waste, pig waste, abattoir waste and food waste to obtain cummulative biogas yield curves followed by development of the digester configurations using the attainable region technique. A hybrid Analytical Hierachy Process and Fuzzy Technique for Order Preference by Similarity to Ideal Solution was used in the selection of plug flow anaerobic digesters for the configurations. The following biogas volumes were obtained at the end of the 30 days retention period; for pig waste, for abattoir waste, for food waste and for pineapple waste. Quantity of feedstock used was 5kg per sample. A novel framework for the selection of multi stage anaerobic digesters has been presented. Optimal digester configurations obtained differ based on substrate used. The selected plug flow anaerobic digesters for subunit were Expanded Granular Sludge Bed for scenario 1, scenario 2 and scenario 3 were Anaerobic Baffled Reactor.
  • Thumbnail Image
    Item
    Prevalence and identification of yam viruses responsible for seed yam degeneration in the Ejurasekyedumase and Atebubu-Amantin Districts of Ghana
    (November, 2018) Marfo, Esther Agyemang;
    Yam viruses are reported to be widespread in all areas where yam is grown. In Ghana, viral diseases are known to cause about 50% of yield reduction on yam. It was for this reason that this research was carried out to manage yam viruses in Ghana. Surveys were conducted in the 2015 and 2016 cropping seasons in two major growing districts, Ejura-Sekyedumase and AtebubuAmantin of Ghana to determine the prevalence of yam virus. There was the need to identify the specific viruses producing the symptoms that were observed during the survey, as such symptomatic leaf samples were taken for analysis at the laboratory using RT-PCR. Out of the 40 leaf samples collected from each district, Ejura-Sekyedumase District had six mixed infections for both Yam mosaic virus (YMV) and Yam mild mosaic virus (YMMV) while eight single infections were recorded for YMMV. Atebubu-Amantin District had 10 mixed infections for both viruses and eight single infections for YMV. Molecular-based diagnostics techniques were also employed to monitor the health status of seven plants (Diosecorea rotundata Poir) established from positive selection, of which five of them did not amplify for any of the two viruses tested while two amplified for both viruses that were tested. Seed yams (‘Dente’, ‘Pona’ and ‘Laribako’) selected in 2015 from symptomless or mildly infected plants (positive selection), as well as those purchased from the Ejura market (farmer practice) and those selected from field diseased plants were established in field experiments in 2016 and 2017 cropping seasons at Ejura and Fumesua using a 3 x 3 factorial in randomized complete block design. The performances of the three seed yam sources were compared for their reaction to yam mosaic virus infection and tuber yield. The three white yam (D. rotundata) varieties used were; ‘Dente’, ‘Pona’ and ‘Laribako’. Plants raised from positive selection performed significantly (P<0.05) better with least virus percentage infection and disease severity scores irrespective of the variety. Positiveiii selection Dente out-yielded farmer practice Dente and diseased Dente by 35 and 66.7% respectively in the 2016 cropping season at Ejura. Similar result was obtained at Fumesua with positive selection Dente out-yielding farmer practice and diseased seed yams by 32.6 and 60.7% respectively. In the 2017 cropping season, even though there was general yield reduction indicating loss of seed yam quality with time, similar trend occurred with positive selection plants performing significantly (P<0.05) better with least virus incidence and severity scores at both locations. Positive selection Laribako produced the highest yield at both locations. With farmers’ current practice of recycling seed yams from one season to another, this study showed that positive selection was a good approach to reducing virus load in farmers’ farms as well as reducing seed yam degeneration while maintaining fairly good yields.
  • Thumbnail Image
    Item
    Analysis of project management practices in the public sector-the case of Weija-Gbawe municipal assembly
    (JANUARY, 2021) Pinkrah, Justice;
    The study was set out to assess the project management practices among MMDAs in Ghana using a case study of Weija-Gbawe Municipal Assembly in the Greater Accra Region of Ghana. The specific objectives were as follow; to identify the current project management practices carried out by the Weija-Gbawe Municipal Assembly and to identify the challenges associated with project management practices by the Weija-Gbawe Municipal Assembly. The study made use of descriptive survey designed to assess the project management practices and the challenges associated with it. A total number of 35respondents were selected from the assembly for the survey. The study used both primary and secondary data. The data was analysed using both qualitative and quantitative approaches. The study found that 80 percent of the respondents sees procurement activities at the Weija-Gbawe Municipal Assembly as a core activity whiles 20 percent sees it as a non-core activity. Also, majority of the respondents indicated that there was no specific unit designated by the assembly to carry out project management related activities and also there were no specific personnel assigned to carry out project management related activities. The study also revealed that the personnel/ units that undertake project management activities at the assembly were identified to be field technician, specific project manager to a project, procurement personnel, contractors, audit unit, M & E personnel and others such as contractors. With respect to the current project management practices by the Weija- Gbawe Municipal Assembly, the study revealed that the topmost project management practices carried out by the assembly were; setting up overall project mission, purpose and goals, effective team building, effective procurement plan, ensuring top management support, instituting a well-laid out project specifications, effective consultations with project stakeholders and setting up project scope. The study also found that the assembly does not effectively practice the following project management practices; project integration, deliberate quality management practices, effective communication among project team members, monitoring and evaluation activities with time management plan being the least practiced. The study found that the top seven most challenges constraints associated with project management practices by the Weija-Gbawe Municipal Assembly identified were; corruption, payment difficulties and delays, poor coordination and communication structures, political interference, delays by contractors, fiscal constraints and extensive controls and as well, poor understanding of procurement practices. The study therefore recommends that the Weija-Gbawe Municipal Assembly should set up a unit to be responsible for project management related activities. It is also recommended that the assembly put more attention and emphasis on the project management practices that they currently fail in terms of implementation. They are; project integration, deliberate quality management practices, effective communication among project team members, monitoring and evaluation activities with time management plan being the least practiced. The assembly should also work to ensure that corruption or its perception is minimized through transparent award of contracts and effective supervision of project delivery devoid from political influences and interference to ensure that projects are delivered in accordance with the right standards. It is finally recommended that personnel in the assembly in charge of project management should be given regular training on project management and its related activities to ensure that they are well equipped to implement projects of the assembly efficiently and effectiveness.
  • Thumbnail Image
    Item
    Assessment of Maize Ear Rot in Major Maize Growing Areas of Ashanti Region of Ghana
    (June, 2014) Herbert, Klay Kieh
    Maize ear rots reduce grain yield quality with implication on food security and health. Information on the types and prevalence of maize ear rots in the major maize growing areas of Ashanti Region of Ghana is scanty. A surveywas, therefore, conducted during the major and minor maize growing seasons to determine the prevalence of maize ear rots and types of fungal pathogens associated in this region. The survey considered 39 and 20 communities in metropolis, municipals and districts during the major and minor seasons, respectively. A total of 44 farmers were interviewed during the survey. The field survey showed a 70% female dominance amongst respondents and a predominantly middle-age farming population. Majority (77%) of the farmers interviewed had only primary school education and about 43% had over two decades of experience with maize cultivation. Most of the farmers obtained their seeds from the Ghana Seed Company, and Obaatanpa appeared to be the variety of choice amongst farmers in the region. About 66% of the respondents alluded to planting their seeds in the month of April and majority (84%) of the farmers observed symptoms of maize ear rot at maturity of the crop. The survey also considered management practices used by farmers to combat maize ear rot. The results showed that majority (68%) of the farmers had no prior knowledge of any fungicides. Roundup, a weedicide, appeared to be the chemical of choice but none of the farmers interviewed used a fungicide. Sun drying of debris appeared to be the popular control method used in the region.The maize samples collected from the communities were taken to the laboratory and analyzed for ear rot pathogens. During the major season, a total of seven fungal pathogens were isolated. For this period, the prevalent fungal pathogen of maize ear rot was Aspergillus flavus, followed by Colletotrichum sp. and the least being Curvulariasp. For the minor season, a total of five fungal pathogens were isolated. During this period, the prevalent fungal pathogen of maize ear rot wasColletotrichumsp., followed by A. flavus and the least being Penicillium sp. The types of maize ear rot identified wereAspergillus flavus,Colletotrichum sp., Trichoderma sp., Fusarium sp., Aspergillus niger, Penicillium sp. and Curvulariasp.Results from the field survey showed that majority of the farmers did not perceive the occurrence and impact of maize ear rots.
  • Thumbnail Image
    Item
    Towards a sustainable procurement in Ghana
    (June, 2014) Muniru, Abdul Aziz
    The study made use of physical, scientific and social science tools. In order to assess sustainable procurement issues, structured questionnaires were circulated, targeting procurement staffs in building and civil consulting outfits, few building and civil engineering contractors, government ministries, Metropolitan, Municipal and District Assemblies and a few manufacturing companies in and around Greater Accra region with building technologists making up the greater percentage. Most of the questions in the questionnaire were designed using Likert scale strategy, which measures respondents’ attitude by asking the extent to which they agree or disagree with most of the issues at stake. The questionnaires were randomly circulated for this study. In all, about 100 questionnaires were circulated of which 56 were received and analysed using descriptive statistical tools like Mean, median, mode and standard deviations. A software called Statistical Package for Social Sciences (SPSS) was used for the data analysis. From the study, one of the key findings was that majority of the people do not adopt effective sustainable procurement practices. The study found out that, the Public Procurement Act, somewhat succeeded in harmonizing the process of procurement in public entities. To a larger extent, however, it has failed to address issues of Green Procurement, as well as issues of effective monitoring and evaluation of procurement activities. To ensure sustainable procurement in Ghana, the Public Procurement Act must be amended to include effective green procurement elements. There must be effective monitoring and evaluation of procurement activities of firms, as well as instituting effective penalizing mechanisms. Sustainable procurement is key to attaining sustainable development, and its attainment depends on efforts of all stakeholders. Through redesigning of its procurement policies and procedures, Government of Ghana can see many multiplier benefits internally and across society as a whole, including efficiency gains, energy usage reductions, financial savings, improved access to services and better working conditions.